论文标题
强烈的自我诱导的非偏置传播，使用非线性PT对称依克隆 - 奈尔 - 零材料超材料
Strong self-induced nonreciprocal transmission by using nonlinear PT-symmetric epsilon-near-zero metamaterials
论文作者
论文摘要
非肾脏传播是单向波传播现象背后的基本过程。在我们的工作中，基于两种碳化硅（SIC）介质设计的紧凑而实用的平价（PT）对称超材料，该介质由气隙隔开，并带有增益和损失缺陷的光子掺杂。我们证明，当SIC作为实用的Epsilon-Near-Zero（ENZ）材料并考虑到其中等的光学损失时，在该PT对称系统中形成了异常点（EP）。此外，甚至更重要的是，由于非线性KERR效应的频率稍微从EP转移，但没有打破PT-对称相，因此强烈的自我诱导的非偏射传播是激发的。从一个方向的透射率完全是统一性，而从另一个方向的传输降低到非常低的值，从而实现了非常高的光学隔离。与被动的非线性非年代谐振剂相比，提出的主动非线性超材料克服了非年份的基本物理界限。强烈的自我诱导的非转向传播是由从相反的入射方向激发时实现的极端不对称场分布。缺陷中电场的显着增强有效地降低了所需的光功能，以触发提出的非线性响应。这项工作可以具有大量的应用，例如用于保护源的非临界超薄涂层或其他敏感设备免受外部脉冲信号，循环器和隔离器的影响。
Nonreciprocal transmission is the fundamental process behind unidirectional wave propagation phenomena. In our work, a compact and practical parity-time (PT) symmetric metamaterial is designed based on two Silicon Carbide (SiC) media separated by an air gap and photonically doped with gain and loss defects. We demonstrate that an exceptional point (EP) is formed in this PT-symmetric system when SiC operates as a practical epsilon-near-zero (ENZ) material and by taking into account its moderate optical loss. Furthermore and even more importantly, strong self-induced nonreciprocal transmission is excited due to the nonlinear Kerr effect at a frequency slightly shifted off the EP but without breaking the PT-symmetric phase. The transmittance from one direction is exactly unity while the transmittance from the other direction is decreased to very low values, achieving very high optical isolation. The proposed active nonlinear metamaterial overcomes the fundamental physical bounds on nonreciprocity compared with a passive nonlinear nonreciprocal resonator. The strong self-induced nonreciprocal transmission arises from the extreme asymmetric field distribution achieved upon excitation from opposite incident directions. The significant enhancement of the electric field in the defects effectively decreases the required optical power to trigger the presented nonlinear response. This work can have a plethora of applications, such as nonreciprocal ultrathin coatings for the protection of sources or other sensitive equipment from external pulsed signals, circulators, and isolators.
